Evidence on age-related differentiation in the structure of cognitive abilities in childhood and adolescence is still inconclusive. Previous studies often focused on the interrelations or the g-saturation of broad ability constructs, neglecting abilities on lower strata. In contrast, we investigated differentiation in the internal structure of fluid intelligence/gf (with verbal, numeric, and figural reasoning) and crystallized intelligence/gc (with knowledge in the natural sciences, humanities, and social studies). To better understand the development of reasoning and knowledge during secondary education, we analyzed data from 11,756 students attending Grades 5 to 12. Changes in both the mean structure and the covariance structure were estimated with locally-weighted structural equation models that allow handling age as a continuous context variable. To substantiate a potential influence of school tracking (i.e., different learning environments), analyses were additionally conducted separated by school track (academic vs. nonacademic). Mean changes in gf and gc were approximately linear in the total sample, with a steeper slope for the latter. There was little indication of age-related differentiation for the different reasoning facets and knowledge domains. The results suggest that the relatively homogeneous scholastic learning environment in secondary education prevents the development of more pronounced ability or knowledge profiles.

Building on Key’s fundamental distinction and Katz’s and Mair’s modifications to this distinction, this chapter describes and analyzes the interaction of German voters and party elites at three distinct levels: the ‘party-in-the-electorate’, the ‘party-in-the-government’ (Key) or ‘party in public office’ (as Katz and Mair put it), and the party organization outside the legislature, particularly the ‘party on the ground’ (Katz and Mair). Our analysis focuses on individual parties and also covers the party system as ‘the system of interactions resulting from inter-party competition’ (Sartori 1976). We will aim to track important continuities in, and changes to, voting behaviour in respect of the main German parties individually and of the party system as a whole, concentrating on the period since unification in 1990. Drawing on a number of theoretical perspectives, including theories of electoral change, theories of organizational reform in political parties (in response to electoral change), and coalition politics at the governmental level, we will develop our argument as follows: after introducing the main parties and analyzing continuities and change in voting behaviour and party membership, we will analyze how political parties have responded to the growing levels of political uncertainty in organizational terms and will seek to address the seemingly paradoxical question why Germany’s party system has remained relatively stable at the governmental level (the party in public office), while parties in the electorate and parties as organizations have become far more fluid and vulnerable. (On the electoral system in Germany, including proportional representation and the statutory minimum of 5 per cent of the national vote a party must achieve to be represented in the Bundestag.